Bladder cancer is a significant cause of morbidity and death. Whole bladder photodynamic therapy (WBPDT) provides an attractive method to treat bladder cancer because it may be used to eradicate the microscopic premalignant lesions which cause uniformly sensitive to photodynamic therapy; and because it has no systemic side effects. Unfortunately, present day methods of photoirradiating the bladder wall are cumbersome, time consuming and inaccurate. PhotoRadiation Systems' Intravesical Laser Catheter and Monitoring System (IVLC-MS) will provide simple, safe and effective WBPDT. This delivery system also will extend the application of WBPDT intracavitary PDT. This delivery system features a balloon which transforms the bladder wall into a sphere of known volume. Passage of a bulb tip treatment fiber into the catheter automatically centers the light emitter in the center of the balloon and bladder wall. A light sensor incorporated into the balloon wall will allow continuous monitoring a light fluence at the bladder wall and, for the first time, provides a method to measure cumulative light fluence during WBPDT. Our initial 2/1/89 SBIR application (IR43 Ca50830-1) describing this delivery and monitoring system was approved (score 199) but was not funded. The present application addresses the reviewers criticisms of our initial proposal, describes progress made since the initial application (development of catheter prototypes, proof of concept testing, and development of a sensing fiber) and outlines our proposal for pre-clinical testing of the IVLC-MS.